Multi-chip modules are rapidly becoming the package medium of choice for high density packaging of ICs. These modules allow for tight IC pitch and high interconnect density.
Methods for achieving I/O with multi-chip modules (MCM) include enclosing in leadless packages, solder bumping from the MCM to a mother-board, or TAB bonding. Provisioning of means for optical fiber I/O is also necessary where optically interconnected modules are used. Examples of applications for optical fiber use include main frame computers, work stations, broadband telephone-based switching stations (where SONET and ATM are implemented), etc.
To make optical fiber I/O in multi-chip modules practical from a manufacturing point of view, methods for separating tight optical tolerances from electrical tolerances must be devised. One method of achieving this goal involves the fabrication of optical fiber device sub-modules, which are pre-fabricated, tested and qualified and then placed in the MCM environment.
The fabrication of a pre-qualified module involves placing one or more polished and/or surface cleaved optical fibers into a module, alignment of the fiber with components of the module and fixing the optical fibers in place. The process must be done automatically to be cost effective.